Apparatus and method for heating an endodontic instrument by infrared radiation

ABSTRACT

An apparatus and method for heating an endodontic instrument by infrared radiation includes a housing defining a chamber. An infrared heating element is positioned within the chamber. The housing includes an aperture and an adjacent holder for holding the endodontic instrument, such as an obturator. The endodontic instrument held by the holder extends through the aperture and into the chamber. The infrared heating element directs infrared radiation toward the endodontic instrument, which heats the endodontic instrument.

TECHNICAL FIELD

The present invention relates generally to an apparatus and method forheating an endodontic instrument, and more particularly, to heating anendodontic instrument such as an obturator for treating root canalcavities.

BACKGROUND

Root canal therapy may be completed in essentially a three step process.First, a dentist, endodontist, or other medical practitionermechanically removes infected pulp from within the internal rootstructure of a tooth. Second, the internal root structure is cleaned anddisinfected leaving a void in the place of the infected pulp. Third, thevoid is obturated or filled with a biocompatible, semi-structuralmaterial.

The voids created within root canal systems during such a root canaltherapy often present highly complex geometries which vary significantlyfrom treatment to treatment. Traditionally during the obturation step,the root canal receives gutta percha, RESILON®, or similar material in asoftened and highly viscous condition. The gutta percha then hardenswithin the enlarged and cleaned root canals, while retaining someresiliency to sufficiently fill the complex voids. However, theexpertise required for such traditional obturation requires significantequipment and many additional procedural steps.

Therefore, to simplify obturation, there is a growing trend in rootcanal therapy to make use of so-called “obturators.” Obturators areessentially a toothpick sized stick of root canal filling material.During the procedure, the practitioner places the obturator in a smalloven to warm and soften the filling material. Once properly heated, theobturator is used to conform the softened filling material to thecomplex geometries of the root canal structure and eventually fill theremaining void. Due to the inherent simplicity of an obturator relativeto more traditional methods, it has become clinically accepted thatobturators allow practitioners to achieve greater success rates withpatient root canal therapies. Thus, patients benefit from less pain andinfection while practitioners benefit from less equipment and decreasedprocedure complexity.

Despite these beneficial outcomes, the acceptance of obturators amongstpractitioners has been hindered by at least three attributes of thesmall ovens used to heat the obturators. First and foremost, these ovensrequire considerable time to “pre-heat” before use. Pre-heating requiresthe practitioner or other office clinician to carefully plan ahead whilesimultaneously performing the procedure, thereby creating additionalcomplexity in what may be an already busy office environment. Secondly,once the oven is pre-heated, the obturator must be placed in the ovenand heated to the proper temperature. Heating the obturator is arelatively time-consuming process that can only be minimized withexcellent planning on the part of the practitioner. Finally, poweringthe oven includes a cord which must be plugged into a nearby poweroutlet, which limits the locations in which the oven may be operated.Moreover, any mistake on the part of the practitioner or other officeclinician in attempting to accommodate this complexity results in idletime and decreased efficiency.

Presently, ovens used in conjunction with obturators rely on naturalconvective heating. The heat is generated by a resistive heating coilelement generally heated from 120° C. to 180° C. After the obturator isplaced within the oven, it is slowly raised to the proper temperaturevia convective heating by the warmed air flowing around the obturator.Unfortunately, the time and complexity required to use these convectiveovens has hindered the wide use of obturators in practice to thedetriment of practitioners and patients alike.

There is a need for an apparatus and method for use in endodonticprocedures, such as root canal therapy, that addresses presentchallenges and characteristics such as those discussed above.

SUMMARY

In one embodiment, the invention provides an apparatus for heating andsoftening a filling material portion of an endodontic instrument byinfrared radiation. The apparatus generally comprises a housing defininga chamber and an infrared heating element within the chamber configuredto generate heat energy. The housing of the chamber includes anaperture. Adjacent to the housing is a holder configured to hold theendodontic instrument such that at least the filling material portion ofthe endodontic instrument extends through the aperture and into thechamber for receiving the heat energy generated by the infrared heatingelement. The axis of the aperture is aligned with a central portion ofthe chamber along an instrument axis. The infrared radiation is directedalong the instrument axis.

Various additional aspects of the apparatus include a heat sink adjacentto the housing that is configured to dissipate a portion of the heatenergy. The housing also includes air vents configured to dissipate aportion of the heat energy. Moreover, a reflective surface is adjacentto the chamber and configured to direct at least a portion of the heatenergy from the infrared heating element toward the filling material ofthe endodontic instrument extending into the chamber.

In yet another embodiment of the invention, the apparatus comprises acore structure and a housing that includes a top cover and a bottom suchthat an infrared heating element is interposed between the top cover andthe bottom and within the core structure. The top cover, bottom, andcore structure thereby define a chamber. Within the top cover is anaperture. Adjacent to the top cover is a holder configured to hold theendodontic instrument extending through the aperture and into thechamber.

As to using an embodiment of the invention, the endodontic instrument isheld such that at least a portion of the filling material of theendodontic instrument extends into the chamber. Within the chamber,infrared radiation is directed at the filling material. The radiationheats and softens the filling material so that the practitioner iscapable of filling the root canal with the softened filling materialportion of the endodontic instrument.

Various additional objectives, advantages, and features of the inventionwill be appreciated from a review of the following detailed descriptionof the illustrative embodiments taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the invention and,together with a general description of the invention given above, andthe detailed description given below, serve to explain the invention.

FIG. 1 is a perspective view of the apparatus for heating an endodonticinstrument by infrared radiation according to an embodiment of theinvention.

FIG. 2 is an exploded perspective view of FIG. 1.

FIG. 3 is a cross sectional view taken on line 3-3 of the apparatus ofFIG. 1.

DETAILED DESCRIPTION

With reference to FIG. 1, an embodiment of the apparatus 10 for heatingan endodontic instrument by infrared radiation includes a housing 12, anaperture 14 through the housing 12, and a holder 16 configured for usewith an endodontic instrument. In the preferred embodiment of FIG. 1,the endodontic instrument is an obturator 18; however, any endodonticinstrument to be heated may be used with the apparatus 10. As such, theobturator 18 includes both a handle 20 and a filling material 22.

Various alternatives to infrared radiation were considered for theapparatus 10; however, further research found these alternativesdeficient in comparison to infrared radiation. Several alternativesincluded forced convective heating, inductive heating, and microwaveheating.

Similar to an industrial heat gun, forced convective heating wouldgenerate a super-heated vortex of air within the apparatus 10 directedtoward the target, obturator 18. This vortex of swirling air wouldsurround and controllably heat the filling material 22 according toseveral properties including the air temperature of the vortex, the rateof convection, and pattern of the vortex. Despite the ability to controlthese properties, forced convective heating proved relatively timesensitive and costly. For instance, decreasing the time to heat thefilling material 22 required superheating the air within the apparatus10, which required additional time to pre-heat the air. Moreover, oncethe filling material 22 was properly heated and the apparatus 10 waspowered off, the super-heated air remaining within the apparatus 10would continue to heat the filling material 22. Thereby, the fillingmaterial 22 would be at a relatively high risk of overheating. Finally,throughout this heating process, the relatively large vortex ofsuper-heated air preferably should be sealed within the apparatus 10 toreduce the risk of exposure to the operator. Sealing the apparatus 10would greatly increase the cost of the apparatus 10. Thus, forcedconvective heating proved considerably time sensitive and costly.

Inductive heating has also been used in targeted heating applications.Inductive heating would focus a rapidly fluctuating electromagneticfield at the obturator 18 to induce an oscillating electrical current.In turn, resistance to the electrical current within the fillingmaterial 22 generates heat therein. However, in this application, thefilling material 22 lacks sufficient conductivity for a reasonably sizedapparatus 10 to efficiently heat the filling material 22.

Microwave heating of targeted objects, such as obturator 18, has alsobeen considered, but been dismissed for material deficiencies of thefilling material 22. Microwave energy typically heats an object whichincludes water, fats, or sugar molecules. Because the filling material22 does not include these molecules, microwave energy simply passesthrough the filling material 22 without generating significant heat.While the filling material 22 could be reformulated to include thesemolecules, downstream complications could negatively impact theeffective use of the obturator 18 in practice.

In view of these alternative technologies, infrared radiation overcomesthese deficiencies in several respects. First, a source of the infraredradiation is readily controllable by the application of electricalcurrent. Second, the application and removal of electrical currentrelatively instantaneously turns on and off the infrared radiation,which greatly reduces the time to pre-heat the apparatus 10 whilereducing the risk of overheating the filling material 22. Third, thefilling material 22 readily absorbs infrared radiation promotingefficient heating in present practice. Fourth, sources of infraredradiation are typically solid state, readily available, relatively lowcost, and highly reliable. Thus, despite additional challenges toinfrared radiation discussed herein, infrared radiation has proven to bethe preferred alternative to heat the filling material 22.

In one aspect of the embodiment, the housing 12 forms the exterior ofthe apparatus 10 so as to insulate an operator from the heat producedtherein. Thus, in a preferred embodiment, the material of the housing 12is plastic or similar thermally insulating material. The housing 12 isgenerally cylindrical with rounded sides and sufficiently flat upper andlower surfaces. Sufficiently flat lower surfaces provide sturdy supportfor resting the apparatus 10 on a desk, counter, or other locationconvenient for the operator. In another aspect of the embodiment, nearthe top of the housing 12 is an aperture 14. The aperture 14 extendsthrough the top of the housing 12 and permits access to the interior ofthe apparatus 10. Sufficiently flat upper surfaces make the aperture 14more apparent and convenient for use with the obturator 18. As shown byFIG. 1, the obturator 18 is inserted into the aperture 14 so that heatgenerated within the interior of the apparatus 10 is directed to theobturator 18 while the housing 12 insulates this heat from a nearbyoperator.

In another aspect of the embodiment shown in FIG. 1, a holder 16 isconfigured to hold the obturator 18. The holder 16 is adjacent to thehousing 12 and aperture 14 thereby holding the obturator 18 in aposition such that the obturator 18 to extends within the interior ofthe apparatus 10. In a preferred embodiment, the holder 16 is positionedabove the aperture 14 so that the obturator 18 dangles within thisinterior under the influence of gravity. Generally, the obturator 18includes the handle 20 for gripping and a toothpick-sized stick of thefilling material 22 connected thereto. The obturator 18 is positioned onthe holder 16 such that the filling material 22 extends into theinterior of the apparatus 10. The holder 16 may be in the form of ahook, hole, channel, slot, or any such structure 16 a capable of holdingthe obturator 18. Moreover, the handle 20 is larger than the structure16 a for holding the obturator 18. Thus, the handle 20 of the obturator18 is properly positioned by the holder 16 without falling into theapparatus 10.

As shown by the embodiment in FIG. 2 and FIG. 3, the housing 12 includesa top cover 24, central body 26, bottom 28, and heater well 30. In oneaspect, the top cover 24 includes the aperture 14. In a preferredembodiment, the top cover 24 also includes the adjacent holder 16. Theholder 16 is a circular ring with a hole therethrough concentricallyaligning with the aperture 14. The holder 16 is positioned within thetop cover 24. The holder 16 and top cover 24 are formed separately andassembled. In one aspect of the embodiment as shown, the holder 16 isformed from material with improved resistance to heat while the topcover 24 is formed from preferably less expensive material.Alternatively, the holder 16 and the top cover 24 may be formed as asingle unit. Additionally, a tab 16 b extends from the circular ring, towhich it is attached, to an axis 31 of the aperture 14. At the end ofthe tab 16 b and through the axis 31 of the aperture 14 is the hook 16 aconfigured to grip the obturator 18. Thus, the obturator 18 is placed onthe holder 16 and along the axis 31 of the aperture 14.

The top cover 24 is secured to the central body 26 of the housing 12.The top cover 24 is secured to the central body 26 by a fastener 32through a dowel 34 and a dowel hole 36. The dowel 34 and dowel hole 36aid in assembly and further limit relative movement. As shown in FIG. 2,the plurality of dowels 34 and dowel holes 36 include the plurality offasteners 32 therethrough to secure the top cover 24 to the central body26. More specifically, a set of three dowels 34, dowel holes 36, andfasteners 32 are so used.

The central body 26 is secured to the bottom 28 of the housing 12 by wayof fasteners 32, as best shown in FIG. 2. The top cover 24, the centralbody 26, the bottom 28, and the heater well 30 serve to define theinterior of the housing 12 that houses a battery 38 and a heating unit40. More specifically, the battery 38 is a lithium-ion battery 38;however, any source capable of providing power to the apparatus 10 maybe used. Furthermore, the battery 38 is attached to the bottom 28.

The heater well 30 is positioned below the heating unit 40 andintegrally formed with the bottom 28. The heater well 30 includes awalled periphery with an open top and a generally solid, planarremovable cover 42 placed adjacent to the bottom 28. The heater well 30serves to collect obturators 18 accidentally dropped by the operatorthrough the aperture 14. The heater well 30 proves useful for collectingdropped obturators 18 in a location relatively apart from the heatingunit 40. In addition, the removable cover 42 includes a snap 42 a and aclip 42 b for removably attaching the removable cover 42 in the properposition covering the heater well 30 as shown in FIG. 3. Two clips 42 bare inserted into matching slots within the bottom 28. Once the clips 42b are so inserted, the removable cover 42 can swing such that the snap42 a is placed adjacent to the bottom 28 and snapped into place. In theevent the obturator 18 drops through the aperture 14, the operator maythen retrieve obturators 18 collected within the heater well 30 byremoving the removable cover 42 from the apparatus 10, discarding thecollected obturators 18, and reinstalling the removable cover 42 intothe heater well 30.

The heating unit 40 is mounted above heater well 30 to the top cover 24so that an instrument axis 44 of the heating unit 40 is aligned with theaxis 31 of the aperture 14. The instrument axis 44 is centrally locatedwithin the heating unit 40 and preferably passes vertically through acentral portion of the heating unit 40. The mounting of the heating unit40 is attached to and below the top cover 24 by a core fastener 46. Asshown in FIG. 2 and FIG. 3, the core fastener 46 acts as a tie rod tocompress the heating unit 40 together. The core fastener 46 extendsthrough the heating unit 40 exposing a screwthread 48 onto which a lowernut 50 a is tightened, thereby compressing the heating unit 40. The topcover 24 includes a mounting boss 24 a into which screwthread 48 isinserted. An upper nut 50 b is also tightened onto the screwthread 48which affixes the top cover 24 to the heating unit 40. Morespecifically, a pair of the core fasteners 46 and mounting bosses 24 aare so used. For exemplary purposes, only one mounting boss 24 a isshown in FIG. 2. The heating unit 40 is affixed to and below the topcover 24 such that the obturator 18 extends through the top cover 24,along the instrument axis 44, and into heating unit 40.

According to the embodiments shown in FIGS. 1-3, the heating unit 40includes a top plate 52, a bottom plate 54, a core structure 56, and aninfrared heating element 58 with electrical connectors 60 attached at astand 62. The core structure 56 is generally cylindrical and sandwichedbetween the top plate 52 and the bottom plate 54 by the core fasteners46. The infrared heating element 58 is generally cylindrical as well,but, in addition, includes a generally planar portion at its peripherywhere the infrared heating element 58 accommodates the stand 62.Furthermore, the core structure 56 has a hollow, annular interiordefining an interior surface and an interior void in which the infraredheating element 58 is positioned. The top plate 52 and the bottom plate54 each include an opening 52 a, 54 a interior of the core structure 56for receiving the stand 62. Moreover, the top plate 52, the bottom plate54, and the core structure 56 each include a pair of fastener holes 52b, 54 b, 56 b for receiving core fasteners 46. In a preferredembodiment, the infrared heating element 58 is mounted to the stand 62,which is held between the bottom plate 54 and top plate 52 adjoined bythe pair of core fasteners 46 within the core structure 56.

The infrared heating element 58 is an annular ribbon extending in avertical direction along the hollow annular interior of the corestructure 56. Moreover, to manufacture the annular ribbon, the infraredheating element 58 is stamped from a continuous sheet of a suitablematerial and then rolled into the generally cylindrical shape, morespecifically the annular ribbon. This is in contrast to a traditionalinfrared heating element which consists of coils. Moreover, the suitablematerial produces heat energy when subjected to an electrical current.At least a portion of the heat energy produced by the electrical currentis infrared radiation. For example, such a suitable material is nichromeconsisting of 80% nickel and 20% chromium. Once rolled, the infraredheating element 58 is crimped to the stand 62. Moreover, the stand 62includes tabs that insert into the openings 52 a, 54 a of bottom plate54 and the top plate 52 to hold the stand 62 and connected infraredheating element 58 in position. In addition, the stand 62 is formed ofelectrically insulated material capable of withstanding the heatproduced by the infrared heating element 58. For example, the stand 62preferably consists of mica.

In a preferred embodiment, at least a portion of the heat generated bythe infrared heating element 58 is managed by the heating unit 40 with areflective surface 64. The reflective surface 64 is positioned withinthe hollow annular interior of the core structure 56 and adjacent to theinfrared heating element 58. The reflective surface 64 at leastpartially surrounds the infrared heating element 58 and the instrumentaxis 44 of the heating unit 40. In a more preferred embodiment, thereflective surface 64 is positioned between the interior surface of thecore structure 56 and the infrared heating element 58. Morespecifically, the interior surface is the reflective surface 64. Thereflective surface 64 is configured to direct at least a portion of theheat generated by the infrared heating element 58 away from the corestructure 56 and along the instrument axis 44 of the heating unit 40.

Another portion of the heat generated by the infrared heating element 58will be absorbed by the heating unit 40 and the air within the heatingunit 40 rather than directed by the reflective surface 64. Thisabsorption and increase in air temperature results in a portion of theheat energy within the heating unit 40 preferably being dissipated to anambient environment. Thus, the heating unit 40 also includes a heat sink66 to decrease the temperature of the heating unit 40. The heat sink 66includes a plurality of fins 68 affixed annularly to the exterior of thecore structure 56. In addition, the heat sink 66 is thermally coupledbetween the heating unit 40 and the ambient environment to dissipate aportion of the heat generated from within the heating unit 40 to theambient environment. The heat sink 66 is composed of material especiallysuitable for dissipating heat, such as aluminum. In a more preferredembodiment, the heat sink 66, the core structure 56, and the reflectivesurface 64 are formed as a unified component. Alternatively, the heatsink 66, the core structure 56, and the reflective surface 64 may beformed separately.

With reference to FIG. 3, the housing 12 defines a chamber 70 in whichthe infrared heating element 58 is positioned. The chamber 70 is furtherdefined by the heating unit 40 or, more specifically, as the hollowwithin the core structure 56.

As shown in FIG. 3, an operator positions the obturator 18 onto holder16 such that the obturator 18 extends downward into the chamber 70. Inthis orientation, the filling material 22 of the obturator 18 is withinthe chamber 70; however, the handle 20 of the obturator 18 may or maynot be entirely within the chamber 70. Preferably, the handle 20 is notwithin the chamber 70 so that the operator may safely touch the handle20 after heating the obturator 18. Within the chamber 70, the fillingmaterial 22 receives the heat energy generated by the infrared heatingelement 58, which softens the filling material 22 for root canaltherapy.

Within the chamber 70, the filling material 22 of the obturator 18 isplaced along the instrument axis 44 of the heating unit 40. In oneaspect of the embodiment, the infrared heating element 58 extends atleast partially around this instrument axis 44. In another aspect, theinfrared heating element 58 is annular and extends coaxially around thisinstrument axis 44. Furthermore, the infrared heating element 58 isoperatively connected to the electrical connectors 60 to a power cord72. The power cord 72 delivers electrical power to the infrared heatingelement 58 by way of the operatively connected battery 38. However, itshould be noted that any other power source, such as any standard walloutlet, may be used to provide power to the apparatus 10.

Still referring to FIG. 3, as power is delivered to the infrared heatingelement 58, infrared radiation is directed at the obturator 18 withinthe chamber 70. The filling material 22 absorbs the infrared radiationthereby increasing its temperature. However, the power delivered to theinfrared heating element 58 increases the temperature of the infraredheating element 58. Moreover, infrared radiation is also absorbed byother components within the apparatus 10. For instance, the materials ofthe infrared heating element 58, the housing 12, the core structure 56,and other components of the heating unit 40 may each absorb infraredradiation. Thereby, the increased temperatures of these components,particularly the infrared heating element 58, generate convective heat.For this reason, the infrared heating element 58 produces heat frominfrared radiation and heat from convection or, as otherwise referred toherein, infrared heat and convective heat, respectively.

In order to minimize the convective heat and maximize the infraredradiation directed toward the filling material 22, the reflectivesurface 64 at least partially surrounds the adjacent infrared heatingelement 58. The reflective surface 64 is configured to direct theinfrared radiation toward the obturator 18, thus increasing the speedand efficiency with which the apparatus 10 heats the obturator 18 to theproper temperature while minimizing the production of convective heatwith other components.

Management of the convective heat produced with the infrared heatingelement 58 is shown in further detail within FIG. 3. Heat sink 66, whichis adjacent to the chamber 70 and in thermal communication with thechamber 70, absorbs excess convective heat for dissipation into therelatively cooler ambient environment. This dissipation of heat intoambient air forces relatively hot air to rise and exit an upper air vent74 a located adjacent to and within the top cover 24 of the apparatus10. As hot air exits the apparatus 10, a vacuum is created in aninterior space 75 within the housing 12 which draws cool air into alower air vent 74 b located near the bottom 28 of the apparatus 10. Inone aspect of embodiment, the upper and lower air vents 74 a, 74 b, areannular passageways surrounding the upper and lower portions of theapparatus 10. More specifically, the upper and lower air vents 74 a and74 b are formed as gaps between the central body 26 and the top cover 24and bottom 28, respectively. Furthermore, the heater well 30 includes aninternal air vent 74 c to promote circulation of cool ambient air aroundthe heating unit 40. In one aspect, the internal air vents 74 c in theheater well 30 are gaps near the open top within the walled periphery toallow air below the heating unit 40 to circulate. Hot air within thechamber 70 and housing 12 is therefore exchanged for cooler ambient airto help maintain acceptable temperatures.

In another aspect of the embodiment shown in FIG. 3, the chamber 70 issized with relatively large dimensions and a relatively large volume inrelation to the obturator 18. More specifically, a relatively smallchamber 70 would make it unnecessarily difficult for an operator toinsert the obturator 18 into the chamber 70 without contacting anddamaging nearby components, such as the infrared heating element 58. Toprotect the infrared heating element 58, the chamber 70 may include aglass shield (not shown) adjacent to the infrared heating element 58.However, such a glass shield decreases the efficiency of the apparatus10. Thus, in the more preferred embodiment of FIGS. 1-3, the volume ofthe chamber 70 is large enough to prevent contact without the inclusionof the glass shield. Thereby, components are placed a substantialdistance from the obturator 18 being inserted through the aperture 14and into the heating unit 40, which decreases the likelihood ofunintended damage from the operator and increasing efficiency of theapparatus 10.

As shown in FIGS. 1-3, the apparatus 10 includes controls for theoperator to use in operation. These controls include a user interface 76and a CPU 78. The battery 38 provides the power to operate the controls.In one aspect of the controls, the operator turns on the apparatus 10 byoperating a control element 80. More specifically, the control element80 is a button 80 that is pushed to turn on the apparatus 10; however,any control element 80 may be so used. Once the apparatus 10 isoperational, the infrared heating element 58 heats to the predeterminedtemperature and remains on a predetermined amount of time, until thefilling material 22 is properly softened by the increase in temperature.Once the heating is complete, the infrared heating element 58 turns offand the obturator 18 may be removed for use by the operator.

Moreover, in yet another aspect of the embodiment, the infrared heatingelement 58 rapidly heats to temperatures between 700° C.-1100° C. Thus,convective heating heats the air adjacent to the infrared heatingelement 58 to a super-heated condition. While it may be possible to heatthe filling material 22 to a desired temperature by both convection andinfrared radiation, controlling the temperature of the obturator 18becomes increasingly difficult at smaller distances. At relativelylarger distances, the obturator 18 is further insulated fromsuper-heated air, which makes output temperatures simpler to controlwith more predictable results. Therefore, in this aspect of theembodiment, a length 82 between the obturator 18 extending along theinstrument axis 44 of the heating unit 40 and the infrared heatingelement 58 is defined such that the filling material 22 absorbs moreheat from infrared radiation than from convection.

The combined features of increased distance between the filling material22 and the infrared heating element 58, relatively large chamber 70,reflective surface 64, heat sink 66, and air vents 74 a, 74 b, 74 ccumulatively serve to minimize the air temperature within the chamber70, thereby reducing the effect of convective heat. For example, thefilling material 22 can be heated to the proper temperature for rootcanal therapy in approximately 5 seconds using apparatus 10.

Additionally, such controlled heating is particularly beneficial in theevent multiple obturators 18 are heated consecutively. For multipleheating cycles, the obturator 18 preferably begins to cool immediatelyafter the infrared heating element 58 is turned off, even while withinthe chamber 70. To achieve immediate cooling during consecutive heating,the embodiment as shown in FIGS. 1-3 preferably maintains average airtemperatures within the chamber 70 below approximately 60° C.Consecutive testing of five obturators 18 with ten seconds between eachtest indicates that the apparatus 10 will peak with average internal airtemperatures between 30° C.-40° C.

To further control the heating of the obturator 18, a sensor 84 isplaced within the chamber 70 to monitor the temperature. Morespecifically, the sensor 84 is a thermocouple. The sensor 84 providesfeedback to the CPU 78 operatively connected to the infrared heatingelement 58. The CPU 78 selects the proper time and/or temperature toturn off the infrared heating element 58. For instance, an operator maychoose to heat consecutive obturators 18, which increases the startingtemperature of the chamber 70 and decreases the time necessary toproperly heat the filling material 22. Thus, the controls include thesensor 84 for feedback to the CPU 78 to improve the overall performanceof the apparatus 10.

Additionally, the CPU 78 and user interface 76 includes a materialselection control element 86. More specifically, the material selectioncontrol element 86 is a material selection button 86 that is pushed toselect the type of filling material 22 to be heated; however, anymaterial selection control element 86 may be so used. Performance of theapparatus 10 is further optimized by selecting which filling material 22is included on the obturator 18. For instance, gutta percha hasdifferent heating properties than RESILON® and this may affect heatingtimes and temperatures. Thus, performance is optimized by selectingsettings predetermined by the CPU 78 to change the amount of heatingtime and/or temperature of the apparatus 10 based on materialproperties. However, the material selection button 86, sensor 84, andother conceivable performance optimizations will be readily apparent toone skilled in the art. For instance, rather than optimizing performanceby adjusting the amount of time to heat the filling material 22, the CPUmay adjust the infrared radiation directed at the filling material 22.

In use during root canal therapy, the operator of the apparatus 10 maybe a dentist, endodontist, or a medical assistant to the dentist orendodontist. The apparatus 10 is positioned at a convenient locationwithin comfortable reach of the practitioner during root canal therapy.The operator places the obturator 18 onto the holder 16. The holder 16holds the obturator 18 adjacent to the chamber 70. By so holding theobturator 18, the filling material 22 of the obturator 18 extendsthrough the aperture 14 and into the chamber 70.

The operator selects the type of filling material 22 to be heated by theinfrared heating element 58 within the chamber 70 by using a materialselection control element 86. This material selection is communicated tothe CPU 78. Furthermore, a sensor 84 senses the temperature within thechamber 70. The sensed temperature is also communicated to the CPU 78.Using the CPU 78, the predetermined amount of time to heat the fillingmaterial 22 is adjusted to an optimized amount of time based on thematerial selection and/or sensed temperature. The operator powers on theinfrared heating element 58 for the optimized amount of time by pushingthe button 80. Because the apparatus 10 is powered by the battery 38,the infrared heating element 58 is remotely powered. However, selectingthe material and/or sensing the temperature within the chamber 70 forcommunication to a CPU for optimizing the predetermined amount of timeis not intended to limit the invention described herein. In thealternative, the operator may simply power on the infrared heatingelement to heat the filling material 22 for the predetermined amount oftime or use any combination of selecting the material or sensing thetemperature to further optimize the apparatus 10.

The infrared heating element 58 generates heat energy, includinginfrared radiation. This infrared radiation is directed to the fillingmaterial 22. Moreover, infrared radiation is also reflected by thereflective surface 64 within the chamber 70, which directs additionalinfrared radiation to the filling material 22. Convective heat is alsogenerated within the chamber 70 by the infrared heating element.However, the filling material 22 absorbs more infrared heat thanconvective heat. This softens the filling material 22 portion of theobturator 18. Once the filling material 22 is properly heated, theinfrared heating element 58 turns off, the obturator 18 is removed fromthe apparatus 10, and the practitioner fills the root canal withsoftened filling material 22.

In one aspect of the embodiment, managing convective heat produced bythe apparatus 10 is helpful to control the heating of the fillingmaterial 22. To manage convective heat, a portion of the heat energyfrom the chamber 70 is dissipated into the ambient environment by theheat sink 66 and air vents 74 a, 74 b, 74 c. The heat sink 66 is inthermal communication with both the chamber 70 and the interior space75. Because the chamber 70 is relatively warmer than the interior space75, heat energy dissipates to the interior space 75. Interior air vents74 c promote interior circulation of the convectively heated air. Theconvectively heated air of the interior space 75 rises within theapparatus 10 and is expelled to the ambient environment through theupper air vent 74 a. In addition, cool air is drawn into the interiorspace 75 of the apparatus 10 through the lower air vent 74 b.

In another aspect of the embodiment, the operator may mistakenly dropthe obturator 18 through the chamber 70 while attempting to place theobturator on the holder 16. Dropped obturators 18 are collected withinthe heater well 30 below the infrared heating element 58. To retrieveobturators 18, the operator removes the removable cover 42 of the heaterwell 30. Once the removable cover 42 is removed, the operator may accessthe dropped obturators 18 for removal from the apparatus 10.

While the present invention has been illustrated by the description ofone or more embodiments thereof, and while the embodiments have beendescribed in considerable detail, they are not intended to restrict orin any way limit the scope of the appended claims to such detail.Additional advantages and modifications will readily appear to thoseskilled in the art. The invention in its broader aspects is thereforenot limited to the specific details, representative apparatus and methodand illustrative examples shown and described. Accordingly, departuresmay be from such details without departing from the scope or spirit ofthe general inventive concept. What is claimed is:

1. An apparatus for heating and softening a filling material portion ofan endodontic instrument by infrared radiation, comprising; a housing,the housing defining a chamber; an aperture in the housing; an infraredheating element within the chamber, the infrared heating elementconfigured to generate heat energy; and a holder positioned adjacent tothe housing and configured to hold the endodontic instrument such thatat least the filling material portion of the endodontic instrumentextends through the aperture and into the chamber for receiving the heatenergy generated by the infrared heating element.
 2. The apparatus ofclaim 1 further comprising a heat sink, the heat sink being adjacent tothe housing and configured to dissipate a portion of the heat energy. 3.The apparatus of claim 1 wherein the housing further comprises air ventsin the housing configured to dissipate a portion of the heat energy. 4.The apparatus of claim 1 further comprising a reflective surfaceconfigured to direct at least a portion of the heat energy from theinfrared heating element toward the filling material portion of theendodontic instrument.
 5. The apparatus of claim 1 further comprising abattery power source, the battery power source electrically coupled tothe infrared heating element.
 6. The apparatus of claim 1 wherein theinfrared heating element comprises an infrared heating ribbon.
 7. Theapparatus of claim 1 wherein the filling material portion absorbs moreheat from infrared radiation than from convection.
 8. The apparatus ofclaim 1 wherein the housing further includes: a heater well; and aremovable cover, wherein the heater well and the removable cover arepositioned below the infrared heating element and adjacent to thehousing such the removable cover may be removed to gain access to theendodontic instrument collected within the heater well.
 9. An apparatusfor heating and softening a filling material portion of an endodonticinstrument by infrared radiation, comprising; a housing including: a topcover; and a bottom; a core structure, the core structure being hollowand interposed between the top cover and the bottom of the housing,wherein the housing and core structure define a chamber; an infraredheating element, the infrared heating element positioned within thechamber; a reflective surface, the reflective surface positioned withinthe chamber and extending around at least a portion of the infraredheating element; an aperture in the top cover; and a holder positionedadjacent to the top cover and configured to hold the endodonticinstrument such that at least the filling material portion of theendodontic instrument extends through the aperture and into the chamber,wherein the infrared heating element is configured to generate a heatenergy and the reflective surface is configured to direct at least aportion of the heat energy at the filling material portion of theendodontic instrument.
 10. The apparatus of claim 9 wherein the housingincludes an air vent configured to dissipate a portion of the heatenergy.
 11. The apparatus of claim 9 further comprising a heat sink, theheat sink configured to dissipate a portion of the heat energy.
 12. Anapparatus for heating and softening a filling material portion of anendodontic instrument by infrared radiation, comprising; a housing, thehousing defining a chamber; wherein the housing includes an air ventconfigured to permit air exchange between the chamber and an ambientenvironment; a heat sink, the heat sink positioned adjacent to thehousing; an aperture in the housing; a holder positioned adjacent to thehousing and configured to hold the endodontic instrument such that atleast the filling material portion of the endodontic instrument extendsthrough the aperture and into the chamber; and an infrared heatingelement within the chamber, the infrared heating element configured togenerate heat energy, wherein the heat sink is in thermal communicationwith the chamber and configured to dissipate a portion of the heatenergy.
 13. The apparatus of claim 12 further comprising a reflectivesurface adjacent to the infrared heating element and configured todirect at least a portion of the heat energy at the filling materialportion of the endodontic instrument in the chamber.
 14. An apparatusfor heating and softening a filling material portion of an endodonticinstrument by infrared radiation, comprising; a housing, the housingdefining a chamber; an instrument axis extending through a centralportion of the chamber; an aperture in the housing; the aperture locatedat the central portion of the chamber; a holder positioned adjacent tothe housing and configured to hold the endodontic instrument such thatat least the filling material portion of the endodontic instrumentextends through the aperture and into the chamber along the instrumentaxis; and an infrared heating element within the chamber, the infraredheating element configured to produce an infrared heat and a convectiveheat, wherein the length from the instrument axis to the infraredheating element is defined such that the filling material portionabsorbs more of the infrared heat than the convective heat.
 15. A methodof filling a root canal with a heat softenable filling material carriedon an endodontic instrument, the method comprising; holding theendodontic instrument with at least a filling material portion thereofwith a holder, the holder positioned adjacent to a housing, the housingdefining a chamber and having an aperture, the filling material portionextending through the aperture and into the chamber; directing infraredradiation from an infrared heating element positioned within the chamberat the filling material portion within the chamber; heating andsoftening the filling material portion with the radiation; and fillingthe root canal with the softened filling material portion.
 16. Themethod of claim 15 further comprising; dissipating heat from the chamberinto an ambient environment with a heat sink.
 17. The method of claim 15further comprising; reflecting the infrared radiation with a reflectivesurface in the chamber.
 18. The method of claim 15 further comprising;drawing cool air from an ambient environment into the chamber through afirst air vent; and expelling heated air from the chamber into theambient environment through a second air vent.
 19. The method of claim15 further comprising; sensing a temperature within the chamber;communicating the temperature to a CPU; and using the CPU to adjust theamount of time that the filling material portion is heated based on thesensed temperature.
 20. The method of claim 15 further comprising; usinga material selection control element to select a type of the fillingmaterial to be heated; communicating the selected material to a CPU; andusing the CPU to adjust the amount of time that the filling materialportion is heated based on the selected material.